Centrifugal tachometer



Oct. 10, 1933. F SCHWElSTHAL 1,929,537

CENTRIFUGAL TACHOMETER Filed Aug. 3l. 1951 2 Sheets-Sheet, 1

2 Sheets-Sheet, 2

F. G. SCHWEISTHAL CENTRIFUGAL TAGHOMETER Filed Aug. 5l, 1931 Oct. 10, 1933.

main boymember, A; and'on which othercas--' Y t drivingl shaft, 20..

i" i. 'l kf,1392,,955237i 4.4.1,9295371 v v n CENTRIEUGALTACHOMETERi;

k application 'August-31,1931; fserial'Nn. "560,515 i 'Y y sfclaims. (Cram-.15j 1 f 'rhepurpcseoffthisfinventionisltogprcvide an improvedA construction 'of `an f instrument for in -1 minuta-oa :rotary shaft, 'obvia'ting' certain character hitherto in use.v

Thefinvention consists in features of constructionzshown indicated in the claimsmlv Inthedrawings: Figure` 1V is a face Viewv bodying this invention.

and described as Figuref2is amagnied Arear'or inner sideelef-A i v L vation'oflthesame with anfenclosing' member'of' .1'5. the case removedtgfordisclosing theinterior n f 5^ i. shaftby togglelinks, 28,"28,.the twolinks'ofseach 'section atthe lineiB- S on.Fi gremoved from, the casing; JH IFigureV is ai sectionat the ure 4."

. Figure is'a ure 5. Figure 'i 'is tionof the arrow '1 onFigurej5. `Figure 81is an. enlargeddetailpdrtion'vof Fig- 'ure ure 3. f

Figure uref* 1 .Y a l Y Referring tothe drawings in detail: :j f

, The instrumentcomprises'ia casing comprising'a is va section vat .the Aline 10971-10 'OnFigi ing parts of the mechanism are mounted., including a iront bezel member.;l A1', for carrying the trans-f parent irontplate or shield',v a,. and the .gradu meinber,A2, in cup form arranged totelescope over the rnlainibody member, as-may beunder` v Ystoodfrorn Figure 3.] l l i l The` dial or faceplate isgraduated for' indiin Vthe graduated 4circle reading in clockwise (ii-- rection in v vhich-the'indei'i hand-D?, isrotated, by increase of speed of. the"r`nechanism,-` is a f driving shaft journaledat 2l in'thec'asing mem: ber, A,'and arranged, as `seenat 20?, fo'rco'upling at its outer endtotheY shaft of the` mechanism whose rotary' speed is Vtobeindicated`- iAt its defects .in Aand'vobjectionsl tol constructions .of this i l the elements and of'Y jan. instrument l em spending in formi-and dimensions tothe cross a ,-FigureA is 1an elevationof allaorti'orirofv themechanismrseen finflike elevation=in Figure 2` 5;-5njonV section at, the'inie :c-c Figanrelevatorr looking'j Y direc? Figure f9- ,is asectionfat theline' on ateddialv or'ivace .plate,fnB,and' a rear .closure cating reyolutions-per minute in hund'reds, that inner end the shaft,v 20,' carriesa ldrvinggear,

trifugal unit is iof conventional construction' as to its` centrifugalV vfeatures,y comprising a cross y head, 26, which is split for clampingrigidlyon thefshaft, l2e, adjacent/ the upper fend bearingl `A K of said shaft, and a'sleeve member, 27,slidingly journaled on thez shaft,f 24, adjacent rand-above the gearjpinion, L23.' The;sleetj'e, 27, is lfurnished atyits upper, end with' a Vcross head,`- 27?', f corre# j head,*26.fVY i vrThe cross heads,l 26 and 2,7%, have their-,correg spondingrends vconnected at opposite sides"of..the

. betweenv said crossV heads lfor :holding .them noremally, spaced apart to .tlie "limit of the toggle link connections describedf;V xi 1j .The sleeve, 2'7,v carries at thelcwer`Y end spaced downwardly fromfthe 'cross' head, 27a; a collar,

' 29,drve-tted onfthe'sleevefsofas to bero'tated ptherewith, and saidcollar has at theupperedge a transaxial lflange, 29a;whose' upper. surface.' is

filat directly vtransverse to the axis of the' shaft;l

'sel

24.. Thisl flange constitutesjthe vineansof opei- Y centrifugal unit, and therebyinaccordancewith' The-mechanism-byiwhiehftiisflange 'actuan the index hand,vv D,`, will -nowbe described.

mountngfthe meChaIlSm there VV.is provided mounting.; frame structuref'comprising Ia plate; v40,k secured at roppositeen'dstothe Inaincasingv member, as seen Aat 4:1;4:1;andfabracketplate,V

if frgmithe plate, f 4o. p

afsteppedbearing, asfseen at lflifin Ythe plate, 40,' isiaspindle', 501,1 of the index hand, D." A small' gearf,:'51 on thissp'indle back of the .mountingv 1 .ating fthe index hand, Dg'in Aaccordan'ce with the i" centrifugal movement v"ofrthe Weightsof. the' the rotary speedof the shaft, 24,an'd the -Journa1ediirthe .bracketpiataaa'aadnaving Y plate, 40, meshesfwith and is'driven by' "ag'ean- 52,;on`ashaft,53,.tjournaledin the plates, 40 andy Y.

421andha-Vingf adjacent i.the platell42, a gear, 54;

Pivotally mounted vlon thebracket '.plate, '42, at 'the' rear side thereof, is a lever element, indicatedr in totality by reference character, F, the pivot member, 55, of this lever member, rigid with said lever member, as hereinafter described, being journaled in both plates, 4() and 42, 4and extended between them, and having rigid with it Y adjacent the plate,'42, and in the plane of the scribed, carries at oneY end, xed on the lever member, '70, 'aV pivot stud, 57, which projects toward the shaft, 24, parallel to the flatA face of the flange, 292i; and said lever member carries pivotallyon the pivot stud, 57, at said end ajshoe, 58, having a flat face, as seen at 58e, for bearing on saidv flat face ofthe flange.

A'spiral spring,` 60, attached at its' inner end tothe spindle, 50, of the index hand, D, is at- .tached at its outer end to a stud, 40, carried by `the plate, 40, said spring being coiled in the direction for reacting on the spindle to resist the rotation ofthe index hand in clockwise direc-V tion away from the'position at which the sector gear, 56,' is stopped on the bracket end, 42X, as

above mentioned-corresponding to a rest position fof: the index hand. 1 l I v '.Uponconsideringthe construction as thus far described, it may be recognized that actuation l of4 the centrifugal unit, causing'the sleeve, 27, to

slide along the shaft, v24, a varying distance, according to. the'rotary speed of the-shaft, 24, derived through the intermeshing gears, 22. and23, from the inleading shaft, 20,'enables the flange, 29a, encountering and engaging the shoe, 58, to rock thelever unit, F, andits rigid pivot member, ",'causing the sector gear 56, to actuate the remainder of the gear train whichconnects said sector gearwith the spindle of the index hand, D, f orirotating Asaid index hand over the-graduated dial. L f i `At this point, for understanding the. adjust? m'entfor calibrationhereinafter described, 4it is noted that of: the, lever. unit the arm to Awhich movement;-iscommunicated Yfrom the centrifugal unit, s'ornf'etimesl hereinafter referred to as the actuated arm of the lever, consistsof the parts, and 71,1Y extending fromithe pivot member,

^ 5,5,` to thev shoe, 58; and thatv the sector gear,

i 56,' constitutes an actuatingarm of the leverl unit;v being the part by which the movement derived from the centrifugal unit 'is communicated to; the registeringelement;`

, Andupon consideration -it willv beY recognized that Withproper calibration; involving vadaptatiGnf3f-thespring'reaction' to the mass' of the lcentrifugal weights, and the adaptationy or ad# justment of thelever .member as to the effective lengthof the lever arm carryingthe shoe,i58,

the resulting speed indicationmay be rendered correctY for indicating the rotary speed ofthe inleading shaft, 20.A f

, in wiufue understood that the adaptation of the springreaction to themass ofthe centrifugal weightsgis, closely "approximated, in the original.

. gear train. The provision for such leverage will i designing of the construction by good engineering judgment and experience; and that the correction of calibration, for which provision must be. maderby adjustability of some elements of the structure, will be concerned with only a relatively small inaccuracy of speed indication, which may accordingly be corrected by a com'- paratively small change in the leverage between l' the centrifugal,` actuated member, 29a, of the centrifugal unit and the index-hand-actuating now be described. Y

Referring to Figures 4 and 5, this lever unit may be seen to comprise the two lever members, 70 and 71. The member, 70, is lodged directly upon the outer surface of the bracket member, 42, and. is connected, as hereinafter described, with` the pivot member, 55, which 'extends through said bracket member; and said lever member, 7), has atthe end opposite the shoecarrying end ofA the lever unit atransversely pro- -V jecting lug or fiangegwa, The lever member, 71, is formedLwitn' a transverselyprojecting lug or ange, 71e.; fand this vlatter lever member is securedrigidly, but adjustably,as and forithe pur-l pose hereinafter described`,` on the pivot, 55, with the flange, 71a, extending toward the web ofA the lever member, 7G, parallel to and inward with respect to the pivot from theliiangeor lug, 70a. A screw, 70C, having a groove, 70d, land engaged therebyrwith' the: flange, 70a, asseen at the slot, 70e, is screwed into the flange, 715, for adjusting the two lever members, 70 'and 7l,=longitudinally of each other for varyingfthe'effective length'fof i the operating arm of the lever "unit`by varying the distance vfrom the lever fulcrum,-the'pivot,

V55,-to the pivot stud, 57, on which the shoe, 58,

is carried, v l

Upon consideration of the construction`described, it will be recognized that change ofl'lc length of the operating arm -of the lever unitV has no effect upon the position of the index hand at the stage of rotary speed of the centrifugal unit, at` which the memberl V29,n by its ange 29a, encountering the shoe, 58, has rocked the 120 lever to a position'parallel with the face of said flange; and for the adjustment forl calibration to-render the indication at the dial at this'stage correct-that is,Y in agreement with a master instrumentV of like construction,-there mustbe 25 provided means for adjusting the index-handoperating gear trainwith respect to the "lever, whose pivot member, 50, is the initial train actuating element. Y

The construction for this purpose will now be described: Referring to Figures 3 and 5, the pivot member, V55, of thelever .unit,'F, which pivot member'carries rigid with it the gear, 56, l by which through the geartrain, 54, 52, 51, the index hand is .actuated against "the reaction of the spring 60,`is drive-tted in abushing ele-` ment, 72, located on said pivot member, 55, betweenthe lever. members, 70 and 71, and incidentally serving to space these levermembers apart. On the upper side of the levermember, I

71, therev is lodgedv flatly a vlever member, 73, which is keyed fast to the bushing, 72, by means of a slotted hub projecting from the upper end of thebushing throughthe lever member, 71, as14r5 seen at 72a in Figure 8. Saidlever varm member, 73, is further secured'to the bushing by a headed screw, 74, set through `the lever arm member, 73, and extending through an arcuate slot, 71C, inthe'lever'member, 7l, and adapted-to be set 150 for clamping'v the lever armA at adjusted 'position within the range'r ofi the slot.

i It'wiu te understood rrom'tnisiqescription that .the 'part can 'beiadijusted aboutitheaxs .0f thejpivot, 55, withinfthe range'pf thef'a, cuate slot, Tl'thereby rotating thewbushing, 72;" tlie' Asector gear shaft orV pivot, "55,",fand the s tor Y tatingttne shaft, vogfoftnej index jhanc, an

gear; ,56, throughi-'a substantial fangle, an ro- `whicl'i thelinnerend'of the spring, f'60;'is sec ed,

through the' angle necessary'to". set the" hand wat the proper, point ofthe Ydial for vindicating thev speed'in accordance' with 'a master instrument.

For the adjustment of the lever'arm, 73, -as described, it is formed at the end which is extended beyond the edge of the lever member, 7l, with a lug or flange, which projects toward theplane of the levermember, 70; and the lever' member,A 7l, hasV a Vcorrespondingand cooperating lever arm, 71h, along whose edge Athe-flange, 71a, above mentioned, is continuous*r projecting toward the plane of the lever member, 70. `Al headed screw, '75, rotatably engaged witlrtlie flange,

A71a, arid screwed through the' flange,A 73a, has

coiled about it, interposed between the flanges,

Y '7111l and 73a, a compression spring, 76,l which reacts for holding the lever arm, 73, stressed away from the lever arm, 71a. Y Y

The slotted head, 75a, of the'v screw, 75aiords means bywhich the operator can adjustVv the screw, '75, and the leverjarm, 73, for the purposes for which such adjustment vis provided.-

Assuming that in the original set-up of the' apparatus at rest positionv of `all the parts, with the index hand held atnzero'postion by the reaction of the spring, 60, that reaction causes the ,lever unit, 70, 71to be swung about the axis of the pivot, 55, carrying the shoe, 58, into en-Y counter with the disk, 29a, and that upon connecting the device with a shaft whose rotary'speed isto be indicated, change of relation between the centrifugal action andthe resistance thereto'is necessary for calibration to obtaincorrect speed indication, it will be recognized that such change may consist in adjustment of the eiective length of the operating arm of the lever unit,'a's'above described, for greater or less angular movement of the index hand from avgiven amount of centrifugally-,caused movement ofthe 'flange disk, 29a. ,t f From thisv description it may bejunderstood that in the 'process of adjustment for correction of calibration the operator 'connects ,the instru- Vment with' avpower-driven shaft controllable as vto speed, which isV also connected withthe shaft of an identically constructed vmaster instrument,

' and regulates the speed of the power shaft to that at which the lever of the master liristrument stands parallel with the voperatinglfa'ce ofthe 'part, 29a; and while'both instruments are runningthe operator adjusts the lever of the instrument to be calibrated, by means of the screw, 75 as abovev described, toca position parallel with the Y operating face of the part29a; and while the parts are in that position the operator may apply the index hand to the. spindle ofthe instrument'whose calibration is being corrected, at the position on the dial correspondingto that ofthe n index hand of the master instrument;

The speed ofthe power shaft being now increased to any desired maximum indicated on the master instrument, the operator, by means of the screw,"70c as described, adjusts the lever arm as to efiective length, to bring thev index hand to position on the' dial agreeing Awith that of the "h nd"filyffftliefmaster instrument-.'- Thus the due to sliding, j y A y A furtherv important feature consists in the selection of the materials forthe'se two slidingly cooperating parts which are-adapted torthus cooperate without necessity for lubrication. This. is effected.v by making the flange member, 29a, if f of stainless steelV with the lflat face highly nished as by polishing, and making the shoe, 58,

of a Vlead and copperalloy, the leadserving for dispensing with lubrication,v and the copper by `.its high ,thermal` conductivity, tending to prevent heading resulting V'from the limited friction;l

gparts made of the nmatey' ofthe two cooperati rials stated; Y The importance of the adjustmentdescribed effected byfthe part, 7,3, rotating the pivot stud,

'center vof the entire assembly which comprises theV pivot stud,- 55, andthe shoe-carrying lever elements and shoe,58.A y ,v

I'claim: l 1; A shaft speed-indicating a centrifugally actuated elementV and, a spedindicating element, and lever means communilever means comprising a lever-'unit havingl an 'actuated leverarm and an actuating lever arm having avpivot-in-common constituting the pivot of the lever unit, rwhereby saidlever arms. are

angularly adjustablefrelativelyk to each other,

fsaid manually operable means comprising means l for holding said two arms at positions to which y Y they are vprogressively adjusted, and vadditional means for securing said arms rigidlytogether in angularly adjusted relation, said means `being manually accessibley andadapted for manual operation to .effect saidv adjustment Vwhile lthe instrumentis running for centrifugal actuation of the registering element.` l

. 2, A shaft speed indicating instrument having ajcentrifugally actuated element and-a speedindicating element,` and.. lever meanscommunicating'move'ment from the centrifugally actuating element to thespeed-indicating element,.said

`55, and the connected gear train,"inay be underi stood upon considering that this adjustment is equivalent to raising rand lowering-the centrifugal unit or the element, 29a, thereof with respect to the registering unit, and the leverunit, F, thereof, or, the centrifugal unit with the Ypart, 29a, being unchanged in position, the :adjustment described is equivalent to adjustment-of the v instrument having, l 'I 12o o cating movement from thev centrifugally actuated.l Y 'element to the speed-indicating element, said lever means comprising a lever unit having an actuated 'lever arm and an actuating lever arm having a pivot-in-comm'on, said pivotv-in-com- 'ramon being the pivot of thelever unit, `and man-g vually operable means for adjusting said lever'. arms angularly with respect to each other about the pivot axis of the lever unit, comprising means securing said arms rigidlyvto each other, wherevby they are maintained in adjusted-"relation :to-'L50 L#011e nesitien .9i the eeueting 'am .and :the-Barts -eetueted :then-eey fier Y012erating the .-registeng e :elementft the .positien ef the .actuated `@uflrllw the ,eenerifugelly Aieletu= 1.1:.ee1 element; ,eemprileipg 4ment 0f .the l*lever* mit @bent wijd pivetznj @l ISCHWEISTHAL- .meanseeuingfsaidams rigidly hte', each other, .wherebyhey 'are maintained in .adjusted releton .toeeeh .Othenthrougheubtherange ef ,meve- 

